本文件提供了一种估算单个字符（但不包括单词或句子）最小易读字体大小的方法，该方法采用自发光或反射模式，用于任何年龄段和任何观察距离、亮度和对比度变化的观察条件下的文档、产品标签、标志和显示器。 本文件适用于设计和评估任何年龄段眼睛没有病理性疾病的人的单个字符的易读性，但不适用于视力障碍（如低视力）的人。本申请特别针对但不限于使用固定字体大小的印刷材料的情况。 附录F给出了该方法对其他语言的适用性。

This document provides a method for estimating minimum legible font size for single characters, but not for words or sentences, in self-luminous or reflected mode, used in documents, products labels, signs, and displays for people at any age and in any viewing condition in which viewing distance, luminance and contrast are varied. This document applies designing and evaluating legibility of single characters for people at any age who have no pathological disorders in their eyes, but not for people with visual impairments such as low vision. The application is specifically directed to, but not limited to, the cases of printed materials where fixed font size is used. Applicability of the method to other languages is given in Annex F.